Understanding Vulnerable Road Users Awareness Messages Generation Dynamics: The Case of e-Bikes

Electric bikes (e-bikes) are one of the major development assets towards green and inclusive urban transportation. Their high speed, up to 25 km/h, comparable to that of small motorcycles and pedelecs, make e-bikes more prone to traffic acci-dents than conventional bicycles. Hence, it is crucial to enhance the safety of these Vulnerable Road Users (VRUs) through Vehicle-to-Everything (V2X) communications, providing connectivity among road entities. The European Telecommunications Standards Insti-tute (ETSI) has specified awareness messages, carrying position and kinematics information, to extend the horizon of vehicles and VRUs. While the generation patterns and relevant performance of such messages have been extensively investigated in the literature when considering vehicles, a few works have analyzed the so-called VRU Awareness Messages (VAMs) transmitted by VRUs, and to the best of our knowledge, none when considering e-bikes. In this work, we focus on e-bikes and, collecting mobility traces of participants with different riding skills in the city of Karlsruhe, Germany, we assess the dynamics of VAMs generated according to ETSI rules and additional triggers suggested by the Fifth Generation Automotive Association (5GAA). The built prototype collects mobility data from the e-bike as well as other context information, thus providing helpful insights about VAM generation patterns and their impact on the network load. Results show a low channel load for all the considered trigger conditions, satisfying the ETSI load constraints.